/*	$OpenBSD: utils.c,v 1.48 2019/06/28 13:34:58 deraadt Exp $	*/
/*	$NetBSD: utils.c,v 1.6 1997/02/26 14:40:51 cgd Exp $	*/

/*-
 * Copyright (c) 1991, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h> /* MAXBSIZE */
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/time.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fts.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>

#include "compat.h"

#include "extern.h"

int copy_overwrite(void);

int copy_file(FTSENT *entp, int exists) {
  static char *buf;
  static char *zeroes;
  struct stat to_stat, *fs;
  int from_fd, rcount, rval, to_fd, wcount;
#ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
  char *p;
#endif

  if (!buf) {
    buf = malloc(MAXBSIZE);
    if (!buf)
      err(1, "malloc");
  }
  if (!zeroes) {
    zeroes = calloc(1, MAXBSIZE);
    if (!zeroes)
      err(1, "calloc");
  }

  if ((from_fd = open(entp->fts_path, O_RDONLY, 0)) == -1) {
    warn("%s", entp->fts_path);
    return (1);
  }

  fs = entp->fts_statp;

  /*
   * In -f (force) mode, we always unlink the destination first
   * if it exists.  Note that -i and -f are mutually exclusive.
   */
  if (exists && fflag)
    (void)unlink(to.p_path);

  /*
   * If the file DNE, set the mode to be the from file, minus setuid
   * bits, modified by the umask; arguably wrong, but it makes copying
   * executables work right and it's been that way forever.  (The
   * other choice is 666 or'ed with the execute bits on the from file
   * modified by the umask.)
   */
  if (exists && !fflag) {
    if (!copy_overwrite()) {
      (void)close(from_fd);
      return 2;
    }
    to_fd = open(to.p_path, O_WRONLY | O_TRUNC, 0);
  } else
    to_fd = open(to.p_path, O_WRONLY | O_TRUNC | O_CREAT,
                 fs->st_mode & ~(S_ISTXT | S_ISUID | S_ISGID));

  if (to_fd == -1) {
    warn("%s", to.p_path);
    (void)close(from_fd);
    return (1);
  }

  rval = 0;

  /*
   * Mmap and write if less than 8M (the limit is so we don't totally
   * trash memory on big files.  This is really a minor hack, but it
   * wins some CPU back.
   */
#ifdef VM_AND_BUFFER_CACHE_SYNCHRONIZED
  /* XXX broken for 0-size mmap */
  if (fs->st_size <= 8 * 1048576) {
    if ((p = mmap(NULL, (size_t)fs->st_size, PROT_READ, MAP_FILE | MAP_SHARED,
                  from_fd, (off_t)0)) == MAP_FAILED) {
      warn("mmap: %s", entp->fts_path);
      rval = 1;
    } else {
      madvise(p, fs->st_size, MADV_SEQUENTIAL);
      if (write(to_fd, p, fs->st_size) != fs->st_size) {
        warn("%s", to.p_path);
        rval = 1;
      }
      /* Some systems don't unmap on close(2). */
      if (munmap(p, fs->st_size) == -1) {
        warn("%s", entp->fts_path);
        rval = 1;
      }
    }
  } else
#endif
  {
    int skipholes = 0;
    struct stat tosb;
    if (!fstat(to_fd, &tosb) && S_ISREG(tosb.st_mode))
      skipholes = 1;
    while ((rcount = read(from_fd, buf, MAXBSIZE)) > 0) {
      if (skipholes && memcmp(buf, zeroes, rcount) == 0)
        wcount = lseek(to_fd, rcount, SEEK_CUR) == -1 ? -1 : rcount;
      else
        wcount = write(to_fd, buf, rcount);
      if (rcount != wcount || wcount == -1) {
        warn("%s", to.p_path);
        rval = 1;
        break;
      }
    }
    if (skipholes && rcount != -1)
      rcount = ftruncate(to_fd, lseek(to_fd, 0, SEEK_CUR));
    if (rcount == -1) {
      warn("%s", entp->fts_path);
      rval = 1;
    }
  }

  if (rval == 1) {
    (void)close(from_fd);
    (void)close(to_fd);
    return (1);
  }

  if (pflag && setfile(fs, to_fd))
    rval = 1;
    /*
     * If the source was setuid or setgid, lose the bits unless the
     * copy is owned by the same user and group.
     */
#define RETAINBITS (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
  if (!pflag && !exists && fs->st_mode & (S_ISUID | S_ISGID) &&
      fs->st_uid == myuid) {
    if (fstat(to_fd, &to_stat)) {
      warn("%s", to.p_path);
      rval = 1;
    } else if (fs->st_gid == to_stat.st_gid &&
               fchmod(to_fd, fs->st_mode & RETAINBITS & ~myumask)) {
      warn("%s", to.p_path);
      rval = 1;
    }
  }
  (void)close(from_fd);
  if (close(to_fd)) {
    warn("%s", to.p_path);
    rval = 1;
  }
  return (rval);
}

int copy_link(FTSENT *p, int exists) {
  int len;
  char name[PATH_MAX];

  if (exists && !copy_overwrite())
    return (2);
  if ((len = readlink(p->fts_path, name, sizeof(name) - 1)) == -1) {
    warn("readlink: %s", p->fts_path);
    return (1);
  }
  name[len] = '\0';
  if (exists && unlink(to.p_path)) {
    warn("unlink: %s", to.p_path);
    return (1);
  }
  if (symlink(name, to.p_path)) {
    warn("symlink: %s", name);
    return (1);
  }
  return (pflag ? setfile(p->fts_statp, -1) : 0);
}

int copy_fifo(struct stat *from_stat, int exists) {
  if (exists && !copy_overwrite())
    return (2);
  if (exists && unlink(to.p_path)) {
    warn("unlink: %s", to.p_path);
    return (1);
  }
  if (mkfifo(to.p_path, from_stat->st_mode)) {
    warn("mkfifo: %s", to.p_path);
    return (1);
  }
  return (pflag ? setfile(from_stat, -1) : 0);
}

int copy_special(struct stat *from_stat, int exists) {
  if (exists && !copy_overwrite())
    return (2);
  if (exists && unlink(to.p_path)) {
    warn("unlink: %s", to.p_path);
    return (1);
  }
  if (mknod(to.p_path, from_stat->st_mode, from_stat->st_rdev)) {
    warn("mknod: %s", to.p_path);
    return (1);
  }
  return (pflag ? setfile(from_stat, -1) : 0);
}

/*
 * If the file exists and we're interactive, verify with the user.
 */
int copy_overwrite(void) {
  int ch, checkch;

  if (iflag) {
    (void)fprintf(stderr, "overwrite %s? ", to.p_path);
    checkch = ch = getchar();
    while (ch != '\n' && ch != EOF)
      ch = getchar();
    if (checkch != 'y' && checkch != 'Y')
      return (0);
  }
  return 1;
}

int setfile(struct stat *fs, int fd) {
  struct timespec ts[2];
  int rval;

  rval = 0;
  fs->st_mode &= S_ISTXT | S_ISUID | S_ISGID | S_IRWXU | S_IRWXG | S_IRWXO;

  ts[0] = fs->st_atim;
  ts[1] = fs->st_mtim;
  if (fd >= 0 ? futimens(fd, ts)
              : utimensat(AT_FDCWD, to.p_path, ts, AT_SYMLINK_NOFOLLOW)) {
    warn("update times: %s", to.p_path);
    rval = 1;
  }
  /*
   * Changing the ownership probably won't succeed, unless we're root
   * or POSIX_CHOWN_RESTRICTED is not set.  Set uid/gid before setting
   * the mode; current BSD behavior is to remove all setuid bits on
   * chown.  If chown fails, lose setuid/setgid bits.
   */
  if (fd >= 0 ? fchown(fd, fs->st_uid, fs->st_gid)
              : lchown(to.p_path, fs->st_uid, fs->st_gid)) {
    if (errno != EPERM) {
      warn("chown: %s", to.p_path);
      rval = 1;
    }
    fs->st_mode &= ~(S_ISTXT | S_ISUID | S_ISGID);
  }
  if (fd >= 0
          ? fchmod(fd, fs->st_mode)
          : fchmodat(AT_FDCWD, to.p_path, fs->st_mode, AT_SYMLINK_NOFOLLOW)) {
    warn("chmod: %s", to.p_path);
    rval = 1;
  }

  return (rval);
}

void usage(void) {
  (void)fprintf(stderr,
                "usage: %s [-afipv] [-R [-H | -L | -P]] source target\n",
                __progname);
  (void)fprintf(stderr,
                "       %s [-afipv] [-R [-H | -L | -P]] source ... directory\n",
                __progname);
  exit(1);
}
